9. Using S/MIME Signatures

Anubis version 4.2 does not yet provide built-in support
for S/MIME encryption or signing. To encrypt or sign messages using
S/MIME, you will have to use external programs. Usually such programs
require the whole message as their input, so simply using
external-body-processor will not work. GNU Anubis distribution
includes a special Guile program, `entire-msg.scm', designed for
use with such programs. For its detailed description, please refer to
Entire Message Filters. This chapter addresses a special case of
using it with openssl to sign outgoing messages.

To use openssl for S/MIME signing, invoke it using
openssl-filter function defined in `entire-msg.scm'. Give
it at least -sign and -signer arguments. Notice, that
you should not specify any input or output files.